The invention relates to apparatus for cutting elongated material into shorter lengths and the means for uniformly removing the cut material. More particularly, the invention provides a means for overcoming centrifugal and adhesive forces that tend to prevent the staple from freely falling from the cutter reel.
Cutters as described by Keith in U.S. Pat. No. 3,485,120 are broadly used for cutting tow into staple length fibers. These cutters include a rotatable reel having outwardly facing cutter blades against which the tow is wound and a fixed pressure roller pressing upon the tow wound around the reel resulting in cutting of the innermost layers of tow by the cutter blades. As cutting progresses a wad of cut staple fibers is forced inwardly between adjacent pairs of blades. Unfortunately, centrifugal forces and interfiber adhesion resist removal of wads of cut fibers by gravitational forces. Thus the wads of cut fibers continue to rotate with the reel and continue to increase in size until either the cutter jams or until chips of cohered staple break off from the wads and fall into the collection hopper. These chips are heavily entangled, difficult to open, and cause subsequent difficulties in mill processing.
Cook in U.S. Pat. No. 3,733,945 recognizes the problems of jamming the cutter and lack of staple openness using cutters described by Keith and as a solution to these problems Cook discloses mounting at least one fixed jet so that it jets air downwardly upon the proximity of the doffing point of the cut fiber through aligned apertures in the cutting reel which rotate past the jet. This assists the gravitational forces in overcoming the effect of centrifugal and fiber-to-fiber forces allowing the cut fiber to fall freely downward. However, Cook's arrangement has disadvantages associated with discontinuous passage of air from the fixed jet through apertures in the reel crossing through the air jet stream. Cook's arrangement is essentially that of a siren and as a consequence produces very high noise levels.
Potter U.S. Pat. No. 4,120,222 is a modification of the known reel type cutter wherein the jet-producing orifices rotate with the reel and by not interrupting jet-air flow, as with Cook, a negligible increase in noise level results, regardless of orifice size or operating speed of the reel.
While the reel-type cutters of the prior art provide a staple exhibiting fairly uniform openness with substantially no fiber chips, a further means has been discovered to assist gravitational forces and injected air to overcome the centrifugal and adhesive forces permitting the cut staple product to fall more freely in smaller tufts.